The knee-jerk filing says something about political tensions in Missouri’s capital. The rhetoric is petty and ugly. And Missourians may not pay any attention to an impeachment trial without talk of illicit sex.

It would just be our luck to go through an impeachment trial without any talk of illicit sex.

Missouri politics — silly tit for tat without the titillation.

But that is what’s cooking in Jefferson City right now — a Monica Lewinsky-less impeachment proceeding against Democratic Gov. Jay Nixon that has insiders scratching their heads.

This week, Rep. Nick Marshall, a Parkville Republican, filed articles of impeachment that allege that in signing an executive order allowing legally married same-sex couples to file joint tax returns in Missouri, Nixon ignored the state constitution. The constitution prohibits the state from recognizing same-sex marriages.

Nixon says he had no choice. The federal tax code is tied to the Missouri tax code, he said. So if married couples file jointly with the IRS, which allows same-sex couples to file that way, then they also must file jointly with the state.

For that, Marshall insists, Nixon is guilty of “willful neglect of duty” and “misconduct in office.”

Talk about unleashing a nuclear holocaust over jaywalking. Why not just file a lawsuit?

More impeachment charges apparently will be filed soon.

Democrats dismissed the whole thing as evidence that the crazies have seized control of House Republicans. The media didn’t get much excited. Nixon’s office labeled it “a publicity stunt.”

Republican House Speaker Tim Jones, who might have doused the kamikaze actions of a few members of his caucus, instead opted to crank things up with a statement that said the allegations “are ones I take very seriously.”

This proceeding is so far-fetched that it won’t result in Nixon being booted from office. Nixon is on track to become the first governor since John Ashcroft in 1993 to complete two full terms in office.

But the knee-jerk filing does say something about political tensions in Missouri’s capital. Nixon and GOP leaders who control the legislature kept cool during Nixon’s first five years in office. They largely worked together on what they could and let the rest go.

Now Washington, D.C.-style rhetoric has made it to the banks of the Missouri. It’s petty and it’s ugly. The only way to drum it out is to elect a new chief executive, and that person won’t take office until January 2017.

Yes, Nixon sometimes pushes his authority to the limit. Republicans have a duty to push back. But going to the mattresses, as they might say in “The Godfather,” eats away at Republicans’ credibility. The next time they cry wolf, no one will listen.